View
202
Download
1
Category
Preview:
Citation preview
California Department of Transportation
Caltrans Precast Concrete CommitteeCaltrans Precast Concrete CommitteeCaltrans Precast Concrete Committee Caltrans Precast Concrete Committee UpdateUpdate
Jim Ma, P.E.Prestressed Concrete Specialist CaltransPrestressed Concrete Specialist, Caltrans
Nov. 3rd, 2010
2010 Caltrans/PCMAC/Consultants Bridge Workshop
California Department of Transportation
Current Committee Members
F it H ff SDFritz Hoffman, SDDouglas Dunrud, SDPhil Lutz, SDManode Kodsuntie, SDEric Fredrickson, OSFPSay-Gunn Low, OSFPJeremy S Wright, OSFPKeith Hoffman, METSTom Ruckman, SpecificationsCheryl Poulin, ConstructionJim Ma, ESPD (Engineering Services Policy Development)Sue Hida, ESPD (Engineering Services Policy Development)( g g y p )
PC Committee Mission and GoalPC Committee Mission and Goal
T P id PRECAST (P li R E ti
MissionMissionTo Provide PRECAST (Policy, Resource, Expertise, Coordination, Assistance, Standards, Training)
P id T h i l S t t D i d
GoalGoal
Provide Technical Support to Design and Construction for Precast Bridge Structures in CAPromote ABC by Using Precast ProductsPromote ABC by Using Precast ProductsPromote Prefabricated Bridge Elements and Systems (PBES) to Support FHWA “EDC” Initiativey ( ) pp
Typical Cast-in-Place Falsework
California Precast Bridge Design ChallengesCalifornia Precast Bridge Design Challenges
Current Bridge Data: CIP 70% +, Precast 25% Current Bridge Data: CIP 70% +, Precast 25% --
WHY ???WHY ???
Precast Advantages:R id i
Precast Challenges:S i i iRapid construction
Minimize falseworkReduce traffic disruptions on-site
Seismic DesignConstruction CostLonger Spanp
Improve safety for traffic and construction workersMinimize environmental impact
Longer Span
Minimize environmental impactIncrease product quality
CONNECTION CONNECTION CONNECTION
Precast Bridge Seismic Design Precast Bridge Seismic Design CONNECTION, CONNECTION, CONNECTION
California Precast Girder Bridge i h Diff C iwith Different Connections
Typical California Precast Girder/Bent Cap Connections:
Drop Bent Cap ConnectionInverted-T Bent Cap ConnectionIntegral Drop Bent Cap Connectiong p pIntegral Bent Cap Connection
Precast Girder Connection Design and DetailsDrop Bent Cap Connectionp p
Continuous superstructurePinned between superstructure and capand capColumn/footing connection has to be fixedE t d PC i d b tt t dExtend PC girder bottom strandsGood seismic connection
Precast Girder Connection Design and DetailsInverted-T Bent Cap Connectionp
Semi-continuous superstructureConsidered as pinned between superstructure and capsuperstructure and capColumn/footing connection has to be fixedS i i h t d iSeismic research study on-going
Precast Girder Connection Design and DetailsIntegral Drop Bent Cap ConnectionIntegral Drop Bent Cap Connection
Continuous superstructureFixed between superstructure and pcapColumn/footing connection could be pinnedGood seismic connection
Precast Girder Connection Design and DetailsIntegral Bent Cap ConnectionIntegral Bent Cap Connection
Continuous superstructureFixed between superstructure and capColumn/footing connection could be pinnedGreat seismic connection
Current Precast Bridge Cost
Current California Bridge Cost
Current PC Committee Working Items
LRFD Precast Guidance Materials for Designers:
1 Bridge Design Aids Chapter 6 (New Wide Flange Girder Box1. Bridge Design Aids Chapter 6 (New Wide-Flange Girder, Box Section, Trapezoidal Section, Voided Slab Table)
2. Bridge Memo to Designers: 11-8 “Design of Precast Prestressed Girders”
3. Bridge Design Practice Manual: Chapter 10 “PC/PS Concrete Girder Design Example”g p
4. Caltrans Standard Drawings:Precast Prestressed I-GirderPrecast Prestressed Bulb Tee Girder (Harped Strands 2 sheetsPrecast Prestressed Bulb-Tee Girder (Harped Strands 2 sheets, Debonded Strands 2 sheets) Precast Prestressed Voided Slab
d id l d Gi d ( d d l )Precast Prestressed Wide-Flanged Girder (under-development)Precast Deck Panel (under-development)
California Department of Transportation
California Precast Girder Inventory and Span Capacity
California Precast-Pretensioned GirdersPrecast Girder Shapes
Common Used ShapesCalifornia I GirdersCalifornia I-GirdersCalifornia Bulb-TeeCalifornia Bath-TubCalifornia Voided SlabsPrecast Box BeamsP t D lt Gi dPrecast Delta GirdersCA WF Girder
California Precast-Pretensioned GirdersCommon Shapes and Span Length SummaryCommon Shapes and Span Length Summary
California Department of Transportation
C lif i Wid Fl Gi dCalifornia Wide-Flange Girder
California Precast Girder Bridge Span CapacityCalifornia Precast Girder Bridge Span Capacityg p p yg p p y
Typical Precast Girder: 30’-180’Post-Tensioned Spliced Precast Girder: 100’-300’Segmental Precast Girder: 200’-450’g
Two Methods for Post-Tensioned Spliced Precast GirdersMethod 1: Splicing Girders Supported on Limited FalseworkMethod 1: Splicing Girders Supported on Limited Falsework
Two Methods for Post-Tensioned Spliced Precast GirdersMethod 2: Splicing Girders on the Ground (Without Falsework)Method 2: Splicing Girders on the Ground (Without Falsework)
PT Spliced Precast Girder Advantages
Very limited falsework or no falseworkLonger spansLonger spansMaximize vertical clearance
Rapid constructionpContinuous superstructure with no jointsIntegral system between superstructure, bentcap and columnsSeismic resistance connectionCould be pinned at column bottomCould be pinned at column bottomSmaller footing sizeAesthetic pleasantAesthetic pleasantLow construction cost
Recommended